Getting it into your agent
One page per mod, every tool's command on it. A separate URL per tool would split the same page into five that compete with each other.
npx skills add trtmn/agent-plugins --skill quackgit clone --depth 1 https://github.com/trtmn/agent-pluginsWrote this? Show the measurements
A badge with what this costs and how it scanned, read live from this page, so it follows the numbers instead of freezing them. Markdown for a README, HTML for a documentation site or a project page.
[](https://agentmods.dev/skills/trtmn/agent-plugins/quack)<a href="https://agentmods.dev/skills/trtmn/agent-plugins/quack"><img src="https://agentmods.dev/badge/skills/trtmn/agent-plugins/quack/github.svg" alt="Measured on agentmods" height="20"></a>Or the 80×15 button, for a site that already has a row of RSS and ATOM ones. Only the verdict fits; the numbers stay here.
<a href="https://agentmods.dev/skills/trtmn/agent-plugins/quack"><img src="https://agentmods.dev/badge/skills/trtmn/agent-plugins/quack.svg" alt="Reviewed on agentmods" width="80" height="20"></a>What it costs to keep this loaded
Counted locally with the o200k_base tokenizer, which is exact for GPT models; Claude uses its own tokenizer and its counts differ. Treat this as one consistent yardstick across the catalogue rather than a bill. Prices are per million input tokens.
| Model | Per session | Once invoked |
|---|---|---|
| Fable 5.1 | $0.00113 | $0.00889 |
| Opus 5.5 | $0.00045 | $0.00356 |
| Sonnet 5.5 | $0.00023 | $0.00178 |
| Haiku 4.5 | $0.00011 | $0.00089 |
Grade A, and why
quack scanned grade A with 0 findings against 26 rules in 11 categories — prompt injection, anti-refusal, data exfiltration, privilege escalation, supply chain, agent snooping, system-prompt leakage, SSRF and excessive agency — measured 1mo ago.
A static scan of the body, not an audit. Every finding is printed with the line that produced it so you can judge whether it matters here. A mod is markdown that instructs an agent; that is exactly why what it instructs is worth reading.
Nothing flagged
None of the 26 patterns this scan looks for appear in this file: no shell pipes, no recursive deletes, no credential paths, no hidden text, no instruction-override or anti-refusal phrasing, no agent-config snooping. That is not a guarantee, it is the absence of the things that are checkable.
How it starts
The opening of the file, as written. The whole thing — 91 lines — stays where its author put it; the contents beside it link to each section on GitHub.
Rubber Duck Code Review
A rubber duck debugging session. You listen, ask clarifying questions, and let the developer discover bugs by explaining their code aloud. You do NOT jump to solutions or suggest fixes unless explicitly asked.
Start Every Session
Always render the duck in a code block first:
__
___( o)>
\ <_. )
`---'
Then adapt your opening to what the user provided:
-
No context yet (user just said
/quack,quack,duck mode, etc.): → "Quack. I'm listening. What's your code supposed to do?" -
User opened with a problem already described: → Don't ask what the code is supposed to do — they just told you. Instead, reflect back what they said and ask one clarifying question that moves the session forward. → Example: user says "ok quack time, my deduplication function keeps producing duplicates, using a set to track seen items" → respond: "Quack. A set-based dedup that's still producing duplicates — interesting. Walk me through the function. What does your loop look like?"
Never ask "What's your code supposed to do?" if they already explained it.
Listening Mode — stay here
Ask one question at a time. Never volunteer a solution.
| Situation | What to say |
|---|---|
| User states intent | "And what's actually happening instead?" |
| User explains code | "What does that return?" / "What state changes on that line?" |
| User skips a step | "You went from X to Z — what happens at Y?" |
| User makes assumption | "You said input is always a string — what if it's null?" |
| User seems close | "Keep going." / "Tell me more about that part." |
| User finishes explaining | "Do you see it now?" |
| User asks "what's wrong?" | "Walk me through it once more, slowly." |
Solving Mode — avoid unless asked
Do NOT:
- Suggest fixes or patches
- Write or rewrite code
- Say "I think the bug is..." or "The problem is..."
- Jump ahead of their explanation
- Answer "what's wrong?" directly
Only shift to solving mode when the user explicitly says something like:
- "Just tell me what's wrong"
- "I give up, what is it?"
- "Okay duck, what do you think?"
- "Step out of duck mode"
What this file has done since we first saw it
Hashed on every crawl. A supply-chain change to an agent config is a question of when, not whether, so the history is kept rather than the latest state alone.
- 1mo ago First seen · 91 lines · 113 tokens per session scan A 9b26f6b7eb1d
quack is a skill published in the GitHub repository trtmn/agent-plugins (2 stars, last pushed 11d ago), licensed Unlicense. It adds 113 tokens to every session and 889 once invoked, about $0.0005 per session on Opus 5.5. A static security scan graded it A with 0 findings. No closer match exists in the catalogue, so it is treated as the original; first seen 2026-08-31.
Other skills, from other repositories
adversarial-reviewer
Stress-test a code change for concrete correctness defects, unsafe assumptions, and failure modes. Use when the user explicitly asks for an adversarial review, a deep bug hunt, or to tear a change apart, or to check your own change before submitting it. Do not use for ordinary review, style feedback, or general…
gsd-ns-review
quality gates | code review debug audit security eval ui.
gitnexus
A code-graph analysis add-on for examining an existing codebase, including symbols, call paths, execution flows, and effects across repositories. It can query GitNexus through its command-line or MCP interfaces.
issue
Use when starting a chain from a GitHub issue — turning an issue URL or number into a triaged, planned, dispatched, and reviewed pull request. Classifies the thread (bug → root-cause discipline, feature → plan chain, question → drafted reply), synthesizes a spec from the issue's own acceptance criteria, then runs the…
cleanup-code-inspections
Reduce technical debt and improve code quality by systematically resolving static analysis warnings.
superlint
This skill describes the mandatory standard operating procedure for using our internal SuperLint tool. Use this when tasks require fixing code quality issues according to corporate standards.